No Interrupt service tee and method

ABSTRACT

A method of replacing a gas main that supplies gas to a recipient through an existing service line includes connecting a first tapping tee to the new gas main and connecting a second tapping tee to the existing service line that communicates with a downstream recipient. Branch passages of the first and second tapping tees are fluidically connected together by a connecting conduit. The new gas main is then tapped with the first tee so that gas flows from the new gas main into the connecting conduit up to the second tee. All air is bled from the connecting conduit between the first and second tees, and the existing service line is then tapped with the second tee so that gas is supplied to the recipient through both the existing service line and the connecting conduit. Gas flow to the recipient from the old main is then terminated. The second tee is a specially configured tapping tee specifically adapted for bleeding air from the connecting conduit that interconnects the first and second tees. This tee also utilizes a non-cylindrical bore for holding the conduit to be tapped to inhibit collapsing of the conduit during tapping operations.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to the art of tappingconduits and, more particularly, to the art of tapping mains and servicelines for purposes of replacing same without interrupting service. Theinvention will be described in connection with gas mains and servicelines, but those of ordinary skill in the art will quickly recognizethat the invention has broader application to other mains and servicelines, especially those designed to supply a fluid to a recipient in anon-interruptible fashion.

[0002] In the installation of new natural gas mains, it is typical tobury the new main in the desired location (usually in parallel with anexisting main) and thereafter connect the existing or new service linesthereto for purposes of supplying gas to recipients by way of respectiveservice lines. FIG. 1 illustrates a prior installation for thetransmission of natural gas from a buried main conduit 10 to a home,business or other recipient 15. Gas is withdrawn from the main 10through a main tee 12, and a gas service line 14 fluidically connectsthe branch passage of the main tee 12 to the recipient 15, typically byway of a meter (not shown). Because older gas mains and older servicelines were typically fabricated from iron, these elements corrode andmust be replaced. In each case, plastic conduit is a preferredreplacement.

[0003] Often, the gas service line 14 is a plastic conduit that has beeninserted into a preexisting iron or other metallic service line conduit13 for the purpose of “insertrenewing” the gas service to the recipient15. In such an operation, the plastic conduit 14 is slidably insertedinto the existing conduit 13 from the recipient end and the distal endof the plastic conduit is sealingly engaged with the existing metallicconduit adjacent the main 10 to prevent gas flow between the existingand new service line conduits. This insert-renewing operation has beenfound to be a highly effective and convenient means for replacing anobsolete service line conduit 13.

[0004] Heretofore, installation of a new main has involved simplycutting or blocking the relevant conduits and inserting the new conduitsinto the gas-flow circuit via tapping tees. For example, with continuingreference to FIG. 1, the service line 14 could be severed at the point18 and thereafter connected to a new main. This, of course, interruptsservice to recipients downstream relative to the cut 18. With gastransmission systems, interruption of service results in theextinguishment of pilot lights, and these must be re-lit by servicepersonnel when gas service is restored. Furthermore, a significantamount of air often enters the gas transmission circuit and must be bledbefore the pilot lights will remain lit. The interruption of gas serviceduring the main and/or service line replacement operation is highlyundesirable and adds expense and inconvenience to the operation whilelengthening the time recipients are without service.

[0005] Another deficiency associated with respect to prior main and/orservice line replacement is that prior tapping tees are not well-suitedfor use on small-diameter plastic conduit, e.g., conduit with less thana two inch outer diameter. With conventional tapping tees, such conduitsometimes partially collapses during the tapping operation, and thisprevents the formation of a good seal between the body of the tappingtee and the outer surface of the conduit.

[0006] In light of the foregoing specifically noted deficiencies andothers associated with convention tapping tees and methods, it has beendeemed desirable to provide a new and improved tapping tee and methodthat overcome these deficiencies and that provide better overallresults.

SUMMARY OF THE INVENTION

[0007] In accordance with a first aspect of the present invention, amethod of replacing an existing gas main that supplies gas to arecipient through an existing service line includes connecting a firsttapping tee to a new gas main and connecting a second tapping tee to theexisting service line. The first and second tapping tees are thenfluidically interconnected with an interconnecting service line, and thenew gas main is tapped with the first tee so that gas flows from the newgas main into the interconnecting service line up to the second tee. Allair is then bled from the interconnecting service line between the firstand second tees, and thereafter the existing service line is tapped withthe second tee so that gas is supplied to the recipient through both theexisting service line and the interconnecting service line. Gas flow tothe recipient from the existing main is then terminated with nointerruption of gas service to the recipient.

[0008] In accordance with another aspect of the invention, a tappingmethod for supplying fluid to a recipient from a new pressurized fluidmain without interruption of service from an existing main and serviceconduit includes connecting a first conduit tap to a new pressurizedfluid main, and connecting a second conduit tap to an existing serviceconduit in fluid communication with a downstream recipient. The firstand second taps are fluidically interconnected with a connectingconduit, and the new pressurized fluid main is tapped with the firstconduit tap. A bleed passage in the second tap is opened and fluid isbled from the new pressurized fluid main and connecting conduit until adesired bleed output is detected. The bleed passage is then closed andthe existing service conduit is tapped with the second conduit tap.

[0009] In accordance with a further aspect of the present invention, atapping tee includes a body member defining: (i) an internal threadedpassage; and, (ii) a conduit-receiving bore in fluid communication withthe internal passage. A cutter has an externally threaded region thatcooperates with the threaded passage of the body member for advancingand retracting the cutter in response to its rotation, and the cutterfurther includes a cutting edge at a first end adapted to cut an openingin a conduit secured in the bore. The tee includes a branch passage influid communication with the internal threaded passage, and aselectively openable bleed passage for venting the branch passage to alocation exterior of the tapping tee.

[0010] One advantage of the present invention is the provision of a nointerrupt service tapping method for replacing gas mains and/or servicelines without interrupting service to a downstream recipient.

[0011] Another advantage of the present invention resides in theprovision of a gas line replacement method wherein the pilot lights ingas recipient's appliances are not extinguished and need not be re-litafter the gas line replacement operation.

[0012] A further advantage of the present invention is the provision ofa gas line replacement method wherein one hundred percent gas isdelivered to the recipient through the new gas line immediately upon gasbeing delivered to the recipient through the new gas line.

[0013] Still another advantage of the present invention resides in theprovision of an improved tapping tee specifically adapted for use intapping relatively small diameter plastic conduit without collapsingsame.

[0014] A still further advantage of the present invention is found inthe provision of a tapping tee with a separate O-ring retainer.

[0015] A yet further advantage of the present invention resides in theprovision of a tapping tee specifically adapted for tapping relativelysmall diameter plastic conduit, wherein the body of the tapping teedefines an ovalized bore for receipt of the conduit to be tapped, withthe major (longer) axis of the bore arranged parallel to the tappingaxis.

[0016] Another advantage of the present invention is found in theprovision of a tapping tee that is specifically adapted for facilitatinga gas bleeding operation.

[0017] Still other benefits and advantages of the present invention willbecome apparent to those of ordinary skill in the art to which theinvention pertains upon reading and understanding the followingspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention can take form in a variety of components andarrangements of components, and from a variety of steps and arrangementsof steps, preferred embodiments of which are disclosed in theaccompanying drawings that form a part hereof and wherein:

[0019]FIG. 1 is a diagrammatic illustration of a conventional prior artgas main and service line installation;

[0020]FIG. 2 illustrates the installation of FIG. 1 and further shows anew gas main and service line partially installed in accordance with thepresent invention;

[0021]FIG. 3A is similar to FIG. 2, but the new gas main and serviceline are fully installed and the old service line is renderedinoperative;

[0022]FIG. 3B is a top plan view of the installation of FIG. 3A;

[0023]FIG. 4 is a side view, partially in section and partially inelevation, of an improved tapping tee formed in accordance with thepresent invention;

[0024]FIG. 5 is a top plan view of an O-ring retainer that forms a partof the tapping tee shown in FIG. 4;

[0025]FIGS. 6 and 7 are views taken along lines 6-6 and 7-7,respectively, in FIG. 5; and,

[0026]FIG. 8 is a flow chart that discloses a no interrupt servicetapping method for main and service line replacement in accordance withthe present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] Referring now to FIGS. 2-8 of the drawings, wherein the showingare for purposes of disclosing preferred embodiments only and not forpurposes of limiting same, FIG. 2 illustrates the previously describedconventional gas installation, along with a replacement main conduit 20and interconnecting service line conduit 32 that are intended to replacethe existing main 10 and part of the existing service line 14,respectively. With reference also to the flow-chart of FIG. 8, themethod comprises a step S1 of installing a tapping tee 22 on the newmain 20, without tapping the new main. The method further comprises astep S2 of installing a second, specially configured “No InterruptService Tee” (NIST) 30 (described below) on the existing service line14, preferably at a location adjacent the recipient 15 (the outer,metallic conduit 13, if any, is removed from the existing plasticservice line conduit 14 as needed for access to the plastic service lineconduit 14). Here, again, the tee 30 is not yet used to tap the serviceline 14. The subject method further comprises a step S3 of fluidicallyinterconnecting the branch passages of the tees 22,30 by way of aninterconnecting service line conduit 32.

[0028] At this stage, gas is still being provided to the recipient byway of the existing main 10 and service line 14. Further, the new main20 is pressurized with gas. Prior to tapping the new main 20 with thetee 22 or the service line 14 with the tee 30, these tees are pressuretested to ensure they are properly installed and seated on theirrespective conduits. If either tee 22,30 fails the pressure test, itmust be adjusted or reinstalled on the relevant conduit before themethod proceeds.

[0029] The method further comprises a step S4 of using the tee 22 to tapthe new main 20 so that gas will flow into the interconnecting serviceline 32 up to the tee 30. Of course, a mixture of gas from the new main20 and air from the interconnecting service line 32 will be trapped inthe interconnecting service line. Accordingly, the method furthercomprises the step S5 of bleeding the interconnecting service line 32using the NIST tee 30 as described in further detail below. A gasdetector G is preferably used to determine when the interconnectingservice line 32 is air-free, i.e., when 100% gas is being bled from thetee 30. When 100% gas is detected by the gas detector G, the bleedingoperation S5 is terminated.

[0030] The method further comprises the step S6 of using the tee 30 totap the existing service line 14 so that gas is supplied to therecipient 15 via both the existing main 10 and service line 14 and thenew main 20 and interconnecting service line 32 (and any portion of theexisting service line 14 downstream relative to the tee 30). Those ofordinary skill in the art will now appreciate that the supply of gasfrom the existing main 10 and the existing service line 14 (upstreamfrom the tee 30) can be terminated by a pinching, cutting, and/orcapping operation as desired without interrupting gas service to therecipient 15. For example, as illustrated in FIG. 3A, the existingservice line 14 is cut or pinched off at a location 36 between theexisting main 10 and the new tapping tee 30. Preferably, the existingservice line 14 is also cut or pinched at a second location 38 betweenthe cut or pinch location 36 and the tee 30. Caps 40,42 are installed onthe open conduit ends resulting from the cuts 38,36 to seal same.

[0031] The tapping tees 12,22 can be any suitable conventional tappingtees as are well known in the art. As noted, the tapping tee 30 (NIST)must be specially configured to accomplish the bleeding operation S5.The tapping tee 30 is preferably formed substantially in accordance withthe tee disclosed in commonly owned U.S. Pat. No. 5,425,395, thedisclosure of which is expressly hereby incorporated by referenceherein. The tee 30 is shown in FIG. 4 of the present application and,except as illustrated and described herein, is identical to thatdisclosed in the aforementioned U.S. Pat. No. 5,425,395.

[0032] The tee 30 is specifically adapted for use in tapping relativelysmall diameter plastic conduit such as that having an outer diameter ofless than about two inches. Specifically, unlike the tee disclosed inU.S. Pat. No. 5,425,395, the body B of the tee 30 (comprising upper andlower separable portions B1,B2 adapted for saddle-like placement about aconduit) defines a non-cylindrical, ovalized bore 50 for receiving andretaining a plastic conduit to be tapped. Thus, the bore 50 is definedso as not to conform to the cylindrical outer surface of a conventionalplastic conduit to be tapped with the tee 30.

[0033] The ovalized bore 50 is preferably defined by a major (longer)axis parallel to the axis L along which the tapping cutter assembly 52moves during tapping operations. The ovalized bore 50 is also defined bya minor (shorter) axis that extends parallel to an axis T that liestransverse (preferably perpendicular) to the cutter axis L. Thus, thoseof ordinary skill in the art will recognize that when the body halvesB1,B2 are fixedly secured about an associated conduit and secured usingthe bolts 54, the conduit held in the bore 50 will deform slightly andconform to the ovalized shape of the bore. Specifically, the associatedconduit held in the bore 50 will deform so that it defines an arch thatis directed against the direction of movement of the cutter assembly 52during tapping operations whereby the cutter assembly penetrates thearched conduit, preferably at the crest of the arch. It has been foundthat, with the conduit ovalized in this manner, the cutting tip of thecutter assembly 52 is able to penetrate the conduit more easily andwithout undesirably deforming or collapsing the conduit which wouldresult in leakage of combustible gas. Because the conduit will notdeform under force from the cutter assembly 52, the seal 70 is betterable to seat on the outer surface of the conduit.

[0034] Unlike the tee disclosed in U.S. Pat. No. 5,425,395, a gas-flowpassage P is defined entirely through the cutter assembly 52. A portionof this passage P defines internal flats or the like 78 adapted forbeing drivingly engaged by a tool used to rotate and, thus, advance orretract the cutter assembly 52 on the axis L. With the presence of thepassage P, gas can flow from the branch passage 74 through the cutterassembly 52 and out of the tee 30 through the tapping tower and a bleedport 31 defined in a cap 72 as described in full detail below. The cap72 and O-ring 76 are used selectively to block undesired gas flow out ofthe tapping tower and bleed port 31 of the tee 30.

[0035] The surface defining the bore 50 comprises an O-ring retainingmember 80 specifically adapted to secure the O-ring 70 in its operativeposition and to shape the O-ring so that it conforms to the bore 50whereby the O-ring 70 will sealingly engage the outer surface of aconduit held in the bore 50. The retainer 80 is adapted for placement ina recess 82 defined in the upper body member B1. When the retainer isconnected to the upper body member B1 in this fashion, an annular grooveis defined between the retainer 80 and a protruding annular lip 86 thatsurrounds the tapping bore 84, and this annular recess is specificallyadapted for receiving and retaining the O-ring 70 therein so that theO-ring concentrically surrounds the lip 86 and bore 84.

[0036] With reference to FIGS. 5-7, the O-ring retainer 80 isillustrated in further detail. It comprises a body 90 defined from arelatively thin (e.g., 0.09 inch) molded plastic material that is ableto flex a limited amount. One suitable material is molded acetalcopolymer. The retainer 80 defines a central aperture 92 adapted forreceiving the projecting lip 86 of the body upper half B1 when theretainer is placed in the body recess 82. The inner surface 94 of theretainer is shaped so that, with the retainer operably installed in therecess 82, the inner surface 94 of the retainer defines a portion of theovalized bore 50. Thus, the inner surface 94 of the retainer is notcylindrical.

[0037] The aperture 92 is defined in the retainer 80 in such a mannerthat first and second O-ring support surfaces 96 a,96 b are defined onopposite lateral sides of the aperture 92. When the retainer is operablyinserted into the recess 82, these surfaces 96 a,96 b are arranged inopposed facing relation with the projecting lip 86 and serve to trap theO-ring 70 against the lip so that no adhesive is required to secure theO-ring 70 in its operative position.

[0038] In line with the above-described tapping method, the tee 30 isinstalled with the existing service line 14 positioned in the bore 50and with the interconnecting service line 32 fluidically connected withthe branch passage 74 by way of a coupling C or other suitable means.Those of ordinary skill in the art will recognize that the bleeding stepS5 of the above-described no interrupt service tapping method isconveniently accomplished simply by loosening the cap 72 of the NIST tee30 and allowing gas to flow from the interconnecting service line 32through the branch passage 74, through the tapping tower of the tee 30by way of the passage P defined in the cutter assembly 52, and outthrough the bleed port 31 defined through the cap 72. For bleedingoperations, the cap 72 must be loosened sufficiently so that the bleedport 31 is able to communicate with the passage P. When the cap 72 isagain fully tightened or advanced to its closed position, gas flow outof the tee 30 through the passage P is prevented because fluidcommunication to the bleed port 31 is blocked by the O-ring 76. Ofcourse, using the exact coupling described in U.S. Pat. No. 5,425,395,the same could be accomplished simply by removing the cap 72 and thecutter assembly (at least sufficiently for gas to flow therepast) forbleeding operations.

[0039] The invention has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations insofar as they come within thescope of the appended claims or the equivalents thereof.

Having thus described the preferred embodiments, what is claimed is: 1.A method of replacing an existing gas main that supplies gas to arecipient through an existing service line, said method comprising:connecting a first tapping tee to a new gas main; connecting a secondtapping tee to the existing service line; fluidically interconnectingthe first and second tapping tees with an interconnecting service line;tapping the new gas main with the first tee so that gas flows from thenew gas main into the interconnecting service line; bleeding all airfrom the interconnecting service line between the first and second tees;tapping the existing service line with the second tee so that gas issupplied to the recipient through both the existing service line and theinterconnecting service line; and, terminating gas flow to the recipientfrom the existing main.
 2. The method as set forth in claim 1, whereinsaid step of bleeding all air from the interconnecting service linecomprises opening a passage in said second tapping tee and bleeding amixture of air and gas from the passage in the second tapping tee until100% gas is exhausted from said passage.
 3. The method as set forth inclaim 2, further comprising connecting a gas meter in fluidcommunication with said passage and using said meter to detect when 100%gas is exhausted from said passage.
 4. The method as set forth in claim1, wherein said step of terminating gas flow to the recipient from theexisting main comprises: severing the existing service line between thesecond tee and the existing main so that first and second open ends aredefined; and, capping said first and second open ends of said existingservice line.
 5. The method as set forth in claim 1, wherein said secondtee is connected to the existing service line at a location adjacent therecipient.
 6. A tapping method for supplying fluid to a recipient from anew pressurized fluid main without interruption of service from anexisting main and service conduit, said method comprising: connecting afirst conduit tap to a new pressurized fluid main; connecting a secondconduit tap to an existing service conduit in fluid communication with adownstream recipient; fluidically interconnecting the first and secondtaps with a connecting conduit; tapping said new pressurized fluid mainwith said first conduit tap; opening a bleed passage in said second tapand bleeding fluid from said new pressurized fluid main and saidconnecting conduit until a desired bleed output is detected; closing thebleed passage in the second tap; and, tapping said existing serviceconduit with said second conduit tap.
 7. The tapping method as set forthin claim 6, further comprising: terminating the flow of fluid to thedownstream recipient from the existing main after said existing serviceconduit is tapped with said second tee.
 8. The tapping method as setforth in claim 6, wherein said desired bleed output is a 100%concentration of fluid.
 9. The tapping method as set forth in claim 6,wherein said fluid is natural gas.
 10. A no interrupt service tappingtee comprising: a body member including: (i) an internal threadedpassage; and, (ii) a conduit-receiving bore in fluid communication withthe internal passage; a cutter having an externally threaded region thatcooperates with the threaded passage of the body member for advancingand retracting the cutter in response to rotation, said cutter furthercomprising a cutting edge at a first end adapted to cut an opening in aconduit secured in said bore; a branch passage in fluid communicationwith the internal threaded passage; and, a selectively openable bleedpassage for venting said branch passage to a location exterior of saidtapping tee.
 11. The tapping tee as set forth in claim 10, furthercomprising: a cap threadably secured to the body member in selectiveblocking relation with the internal threaded passage, said cap definingsaid bleed passage whereby rotation of said cap relative to said bodymember in a first direction opens said bleed passage, and rotation ofsaid cap relative to said body member in a second direction closes saidbleed passage.
 12. The tapping tee as set forth in claim 10, whereinsaid bore is non-cylindrical.
 13. The tapping tee as set forth in claim10, wherein said bore is ovalized and defined by a major axis and aminor axis.
 14. The tapping tee as set forth in claim 13, wherein saidmajor axis is arranged parallel to a longitudinal axis of said internalthreaded passage.
 15. The tapping tee as set forth in claim 14, whereinsaid minor axis is perpendicular to said longitudinal axis.
 16. Thetapping tee as set forth in claim 10, further comprising an O-ringretaining member releasably connected to said body and partiallydefining said bore, said O-ring retaining member and a portion of saidbody defining an O-ring receiving groove therebetween when saidretaining member is connected to said body.
 17. The tapping tee as setforth in claim 16, wherein said groove is concentric relative to saidinternal passage.
 18. The tapping tee as set forth in claim 17, furthercomprising an O-ring seated in said groove and adapted for sealinglyengaging an outer surface of an associated conduit positioned in saidbore and said body member, wherein said O-ring retaining memberpre-shapes said O-ring to at least substantially conform to the outersurface of an associated conduit positioned in said bore.
 19. Thetapping tee as set forth in claim 18, wherein at least a portion of saidbleed passage defined through said cutter defines a driving surfaceadapted for being drivingly engaged by a tool for purposes of rotatingsaid cutter in said internal threaded passage.
 20. The tapping tee asset forth in claim 19, further comprising a hollow sleeve releasablyconnected to said cutter, said sleeve adapted for engaging and beingfixedly secured to an associated conduit coaxially in an opening formedby said cutter when said cutter is advanced into and cuts said openingin said associated conduit.